Large-scale rotating systems with blades connected to a main shaft have been used for a long time for, for example a field of technology with large-scale rotating systems is the field of horizontal axis wind turbines. It is known to control the pitch (longitudinal rotational state) of the blades during operation in order to optimize the efficiency of operation of the rotating system.
In rotating systems such as wind turbines, the main bearing, which connects the main shaft with a fixed structure—the nacelle in a wind turbine—is subjected to substantial and varying forces during operation.
In order to improve the availability/up-time and life span of, for example, a wind turbine, various bearing related parameters may be monitored, such as, for example, vibrations, lubricant pressure, lubricant quality, lubricant temperature and bearing load
Although the monitoring that is currently described in the art helps the scheduling of maintenance and prediction of failures before they occur, and thereby may improve the availability of wind turbines and other similar rotating systems, failure modes that are not detected in time may still exist.